1. Field of the Invention
The present invention relates to a process for preparing an orange oil, and an orange oil.
2. Discussion of the Related Art
Valencene is contained at 0.2 to 0.6% by weight in an orange essence oil, which is obtained by squeezing fruit of oranges, a group of plants belonging to the genus Citrus in the family Rutaceae. Ninety percent by weight or more of the orange essence oil is accounted for by terpenes having low boiling points (200° C. or lower), mainly composed of limonene, which have only a low contribution to the aroma of the oil. Therefore, it is not so difficult to concentrate valencene up to about 100-folds by distilling off these terpenes. Generally, commercial products having valencene concentrations of 70 to 90% by weight, obtained by concentrating an orange essence oil by distillation, are available in the market (Perfumer & Flavorist, Vol. 21, May/June, p. 9, 1996). Additionally, valencene is also contained in the essential oil of a fruit peel, known as an orange cold press peel oil, or in an oil obtained by distilling pulp or the like after squeezing the fruit. Since the major components of these oils are likewise terpenes, mainly composed of limonene, valencene in the oil can be easily concentrated up to about 100-folds. However, since the valencene content in the oil is very low (0.02% by weight) as compared to that in the essence oil, the valencene concentration increases only up to 2 to 3% by weight even when the oil is concentrated 100-folds. In addition, since the oil concentrated so as to have a valencene concentration of 2 to 3% by weight contains a large amount of components having boiling points slightly lower than that of valencene, it will not be easy to further concentrate the oil. There have not yet been known to date any processes for preparing an oil containing valencene at a high concentration from these oils.
Moreover, the currently marketed orange oils containing valencene in an amount of 70 to 90% by weight are prepared by concentrating an orange essence oil obtained by squeezing fruit. Therefore, the orange oils have limitations in the amount of production and are expensive, thereby giving rise to causations for the limitations in the amount of use and applicability. Hence, there is an earnest desire for an orange oil that is inexpensive and high in valencene concentration.
In addition, since the currently marketed orange oils containing valencene in an amount of 70 to 90% by weight have an off-flavor like those of higher fatty acids and an undesirable taste, use of the orange oils has been also limited by this off-flavor or the like. Furthermore, an essential oil prepared by concentrating an orange essence oil has limitation in the amount of production and is expensive, thereby giving rise to causations for the limitations in the amount used and applicability. Therefore, there is an earnest desire for an inexpensive orange oil containing valencene free from an off-flavor.